Preferential looking (PL) has met the challenge of acuity testing in the pediatric eye clinic. However, limitations of PL have become evident. Amblyopia may be underestimated or not detected by PL grating acuities. Patients with severe ocular or neuro-ophthalmic disorders may be inadequately evaluated; in some patients, who do not appear blind in other respects, PL acuity is very poor or impossible to test. The proposed research will develop new stimuli and PL methods to: (1) improve the sensitivity of PL to disorders of central vision, particularly amblyopia, and (2) examine the peripheral vision of infants and young children. Computer and video technology will provide the flexibility to assess both central and peripheral vision. Tests for peripheral vision will be studied in infants with normal eyes first and later in infants who have eye and/or brain disorders. In addition, an LED perimetric method, with which peripheral vision of normal 2- to 5-year-olds and pediatric patients has been successfully tested, will be adapted to infants. To investigate central vision, studies will be conducted to maximize infants' grating acuity, and central and peripheral acuity will be compared. Study of infants' discrimination of more complex stimuli than simple gratings may enable better methods to test amblyopic infants. To assess visual fields, the normal development of infants' sensitivity to spots of light varying in size, intensity and eccentricity will be investigated. These data will provide parameters with which to examine patients using methods of kinetic and/or static perimetry. Examination of visual fields could provide previously unavailable, quantitative information about visual function of young patients and could contribute to their medical management, as it does in older patients. Together, these studies of central and peripheral vision could improve the specificity and sensitivity of PL to visual deficits caused by a variety of pediatric ocular and neuro-ophthalmic disorders.